Flash IRT is a thermal transient technique that uses a flash source, an infrared camera, and an image processor to analyze a structure. In one approach, one or more short pulses of high thermal energy are applied to a thermally-conductive surface of a structure using a flash source. An infrared camera is then used to monitor and record thermal transients of the surface as heat disperses into the structure and the surface returns to its normal temperature. For instance, an infrared camera can be used to capture images of the surface before and after the pulses are applied.
Further, the images can then be analyzed using various image processing techniques in order to discriminate between different features and materials. In practice, material imperfections, such as voids, delaminations, or cracks, can affect the cooling of the surface by causing an area of the surface to cool down faster or slower relative to other areas of the surface. Image processing algorithms can analyze a sequence of images and enhance the contrast of relatively warm (or cold) spots on the surface, which may be indicative of material imperfections. Further, image processing algorithms can also be used to assist in the evaluation and/or characterization of any anomalous cooling behavior.
Railcar axles of railcar wheelsets are important components of modern railcars, and are designed to withstand large amounts of stress. However, over time, railcar axles can sometimes experience failures resulting from axle fatigue. In some cases, a crack can form on the surface of a railcar axle, weakening the strength of the railcar axle. If the crack is undetected, the crack can lead to a failure, such as an axle fracture. Accordingly, there is a need to identify surface cracks on railcar axles, in order to repair or replace them before failures occur.
Various approaches to detecting surface cracks on railcar axles exist. As one example, ultrasonic inspection can be used to inspect a surface of a railcar axle. As another example, an inspector can apply a liquid dye to a surface of a railcar axle, and observe the penetration of the liquid dye into the surface.